Kiddo talked me into Minecraft. Today we made obsidian from a pool of lava, and gathered enough to make a nether portal. We got back from the nether OK, but it sent us to a new portal hundreds of blocks away, in an unexplored cavern…under the ocean.
We spent all afternoon tunneling up (slowly) and over so we could come out on dry land. A few close calls with water, but we made it!